Various devices have been described to prevent compromise of lock systems. See for example, U.S. Pat. No. 2,785,565; U.S. Pat. No. 4,073,172; U.S. Pat. No. 4,397,168; and U.S. Pat. No. 4,522,048.
Dead bolt locks typically include a latch pin which extends through an arm which arm is joined to the bolt. The latch pin drives the bolt between its extended and retracted positions when a key is turned. If the latch pin is exposed it may be engaged by a pick and the pick can then move the latch to retract the bolt.
It has been discovered that almost all commercially available dead bolts, which have an upper exposed latch pin, and almost all commercially available latch bolt lock sets can be compromised without defacing or injuring the lock itself. A hole is drilled into the door to provide a passageway between the outside of the door to the upper portion of the dead bolt where the pin is or to that portion of the latch lock where the ears are located. A pick is inserted into the hole and the lock can be opened.
Applicant's invention, in one aspect, is directed to structures adapted to be secured to existing lock sets to prevent such a compromise.
The invention, in one aspect, is a sleeve adapted to engage a bolt frame. The sleeve when so engaged encases the latch pin which drives the bolt and thereby denies access to the latch pin from a location exterior to the bolt. In another aspect, the invention comprises the sleeve in combination with a dead bolt assembly.
The invention in still another aspect comprises a hollow cylindrical sleeve with a tongue extending from one end thereof. The sleeve is adapted to be engaged to the cylinder of a latch lock assembly. The tongue is spaced apart from and extends over the ears of the assembly. This sleeve prevents access to the ears from a location exterior to the lock assembly. The invention, in a still further aspect, comprises the cylindrical sleeve in combination with a latch lock assembly.
In a still further aspect of the invention, a dead bolt lock assembly is provided wherein an arm which extends from the bolt has its under surface configured to engage the latch pin.